The purpose of this project is to investigate the molecular and cellular basis of the intracellular interactions that control the conjugation response of the yeast Saccharomyces cerevisiae. These studies will involve: elucidation of the mode of action of alpha-factor, the mating specific oligopeptide pheromone released by alpha haploid cells; examination of alpha-factor expression; investigation of the role of microtubules in the control of the cell division cycle by mating pheromones; characterization of the propertiesof the surface molecules that mediate mating adhesion; and the selection and examination of mating-defective mutants. These experiments should provide important information on the mechanisms of developmental and morphogenetic control in eukaryotes.